Gas treatment plants are typically used in large-scale plants like oil and gas facilities, gas cleaning plants, carbon dioxide capture facilities, liquefied natural gas (LNG) plants, oil refineries, petrochemical facilities or chemical facilities. In such large-scale plants fluid streams occur which contain acid gases such as CO2, H2S, SO2, CS2, HCN, COS or mercaptans. These fluid streams can be, for example, gas streams (such as natural gas, synthesis gas or heavy oil or heavy residues, coke-oven off-gases, refinery gas or reaction gases formed in the partial oxidation of organic materials, for example coal or mineral oil) or liquid or liquefied hydrocarbon streams, such as LPG (liquefied petroleum gas) or NGL (natural gas liquids). The removal of the acid gases from these fluid streams is desirable for various reasons.
Before these fluids can be transported or further processed, the acid gas content of the fluids must be markedly reduced. CO2, for example, must be removed from natural gas, since a high concentration of CO2 reduces the calorific value of the gas. Furthermore, CO2, in combination with the water frequently entrained in fluid streams can lead to corrosion on pipes and fittings.
The removal of sulfur compounds from these fluid streams is important for various reasons. For example, the sulfur compound content of natural gas must be reduced by suitable treatment measures immediately at the natural gas source, since the sulfur compounds, together with the water frequently entrained by natural gas, also form acids which act corrosively.
For the transport of the natural gas in a pipeline, therefore preset limit values of the sulfurous impurities must not be exceeded. Furthermore, numerous sulfur compounds, even at low concentrations, are foul-smelling, and, in particular hydrogen sulfide, toxic.
In this area companies need to make major multi-million-dollar investment decisions about the most appropriate capacity and functionality of the facility. Since there are many potential configuration and design options for the gas treatment plants, it is difficult to identify viable options and to select the optimal gas treatment plant design. Therefore, a design process is followed to find an optimal gas treatment plant design for given conditions. The design is then implemented in the physical gas treatment plant. Such design processes are highly complex technical tasks, since the envisaged operation of the gas treatment plant with multiple gas treatment units depends on various parameters such as the inlet stream composition, the treatment solution properties, dimensions of the gas treatment units or the thermodynamic environment in gas treatment units. Correlations between these parameters further increase the complexity. As a result, present design methods require a large amount of input data to create viable results reflecting the physical gas treatment plants operation and output properties.
EP 2 534 592 A2 describes methods and compositions computer modeling apparatuses including an input unit enabling user specification of a subject facility design based on limited data. The subject facility design includes design alternatives, and a processor routine coupled to the input unit and responsive to the user specification by forming an input data set to a rigorous simulation modeler to model the subject facility design. The rigorous simulation modeler requires input beyond the limited data.
One problem arising when using such applications is that the user needs to define several input parameters including correlated input parameters. Based on these specifications the composition of the treated outlet gas is calculated. For achieving a specified composition in the treated outlet gas, the designer needs to manually change input parameters. In addition, the complex calculation can easily lead to undesirable and/or physically not meaningful process conditions and unreasonable designs. Such conditions can even lead to non-convergence of the calculation, which in turn leads to a lot of manual and time-consuming iteration steps, which make the design process very tedious and inefficient.
Accordingly, it is an object of the present invention to provide an improved process for designing gas treatment plants, which leads to a significant simplification of the process, reduces the burden on the user and allows to streamline and accelerate the process of implementing gas treatment plants.